Karl Siebrecht

Former aQuantive executive Karl Siebrecht plans to join Seattle online advertising startup AdReady as president, according to a source familiar with the plans.

Siebrecht and AdReady executives could not be reached for comment, but the former president of aQuantive's Atlas unit notified Microsoft employees on Friday. Siebrecht joined Microsoft as a general manager following the software giant's $6 billion acquisition of aQuantive.

AdReady raised a $10 million venture round in 2007 from Khosla Ventures, Bain Capital Ventures and Madrona Venture Group. And Siebrecht has some roundabout connections to two of those firms.

[Post updated with comments from AdReady CEO Aaron Finn and Karl Siebrecht]

Before arriving at aQuantive, Siebrecht served as manager for strategic marketing and private equity transactions at Bain & Company. (Bain Capital is an offshoot of the Boston consulting firm).

Furthermore, last month, former aQuantive CEO Brian McAndrews joined Madrona as a managing director.

But it was neither of those connections that led to Siebrecht joining the display advertising startup, according to Kara Swisher at All Things D. She reports that it was advisory board member David Rosenblatt -- a former Google executive who previously served as CEO of aQuantive competitor DoubleClick -- who made the introduction.

Aaron Finn currently serves as AdReady's president and CEO, though it appears that the former Classmates.com executive is giving up one of those roles in order to strengthen the management bench.

AdReady will need some help as it looks to fend off competition from Google, which has set its sights on the self service display advertising category.

AdReady recently inked a partnership with Yahoo. Its technology also is used by companies such as The New York Times, Univision and The Atlanta Journal-Constitution.

The AdReady technology allows small advertisers like real estate professionals or car dealers to easily create display ads, and then target them to certain demographic groups on the online publishers' Web sites.

Siebrecht also serves as chairman of Evoworx, a Seattle software startup that is trying to help make homes more energy efficient.

Update: AdReady CEO Aaron Finn had this to say about the addition of Siebrecht: "We are extremely excited to have Karl on board and really think it says a lot for the progress AdReady has made, and really creates a lot of opportunity for us in the future." Finn also noted that Siebrecht will hold the chief operating officer role at AdReady.

Update: Here are comments from Karl Siebrecht: "I am very excited to join Aaron and the team at AdReady. Very impressive technology, solid traction with customers and a great team."